Spring中已引入jackson相关依赖,无须在pom中再引入相关依赖,若再引入相关依赖,则会报错创建bean异常。
写一个PlayerStar的实体类,实体类主要体现篮球明星的名字、年龄、业余爱好、朋友、年收入等信息,为了尽可能地演示Jackson的序列化与反序列化功能,将数组、List、Map都融合到这个类里面。并通过getInstance初始化篮球明星Jordan这个对象。
@Data
public class PlayerStar {
private String name;
private Integer age;
private String[] hobbies; //业余爱好,数组
private List<String> friends; // 朋友
private Map<String, BigDecimal> salary; //年收入 Map
//初始化一个对象用于测试
public static PlayerStar getInstance(){
PlayerStar playerStar = new PlayerStar();
playerStar.setName("乔丹");
playerStar.setAge(45);
playerStar.setHobbies(new String[]{"高尔夫球", "棒球"});
Map<String, BigDecimal> salary = new HashMap<String, BigDecimal>() {{
put("2000", new BigDecimal(10000000));
put("2010", new BigDecimal(62000000));
put("2020", new BigDecimal(112400000));
}};
playerStar.setSalary(salary);
playerStar.setFriends(Arrays.asList("kobe", "curry", "james"));
return playerStar;
}
}
@Test
void testObject2JSON() throws IOException {
//获取对象实例
PlayerStar player = PlayerStar.getInstance();
//ObjectMapper作为Jackson的API工具类存在
ObjectMapper mapper = new ObjectMapper();
//将player对象以JSON格式进行序列化,并将序列化结果写入文件
mapper.writeValue(new File("d:\data\jackson\player.json"), player);
//将player对象以JSON格式进行序列化为String对象
String jsonString = mapper.writeValueAsString(player);
System.out.println(jsonString);
//将player对象以JSON格式进行序列化为String对象(格式美化)
String jsonInString2 = mapper.writerWithDefaultPrettyPrinter()
.writeValueAsString(player);
System.out.println(jsonInString2);
}
@Test
void testJSON2Object() throws IOException {
ObjectMapper mapper = new ObjectMapper();
//从文件中读取JSON字符串,反序列化为java对象
PlayerStar player = mapper.readValue(new File("d:\data\jackson\player.json"), PlayerStar.class);
System.out.println(player);
//将JSON字符串反序列化为java对象
String jsonInString = "{\"name\":\"乔丹\",\"age\":45,\"hobbies\":[\"高尔夫球\",\"棒球\"]}";
PlayerStar jordan = mapper.readValue(jsonInString, PlayerStar.class);
System.out.println(jordan);
}
可以使用 @JsonProperty来影响序列化和反序列化对象属性的重命名。
@Data
public class PlayerStar {
@JsonProperty("playerName")
private String name; //将属性name序列化为playerName,同时影响反序列化
String jsonInString = "{\"name\":\"乔丹\",\"age\":45,\"hobbies\":[\"高尔夫球\",\"棒球\"]}";
PlayerStar jordan = mapper.readValue(jsonInString, PlayerStar.class);